Shoe sole

ABSTRACT

A shoe sole is coupled with an upper to define a foot compartment characterized by a fore-foot portion associable with metatarsals and phalanges, a mid-foot portion associable with the arch, and a hind-foot portion associable with the heel. A flexure plate, underlying the 2nd, 3rd, and 4th metatarsal-phalangeal joints of a foot when enclosed within the foot compartment, is disposed within the fore-foot portion between the foot compartment and the outer surface of the sole. During bipedal locomotion, the flexure plate deforms in response to the transfer of a wearer&#39;s weight from the mid-foot portion through the fore-foot portion, and rebounds in response to the transfer of the wearer&#39;s weight off the fore-foot portion. The deforming and rebounding of the flexure plate enables controlled transfer of the wearer&#39;s weight from the mid-foot portion sequentially to the little toe, the big toe, and the three middle toes.

BACKGROUND OF THE INVENTION

Selected footwear sole designs, inserts, and like orthotic devices, may be utilized to address anomalies in foot physiology, posture, and gait. Known devices may be directed to supporting the arch and/or cushioning the foot, particularly the heel. Attempts to correct foot-related anomalies may devote relatively little attention to the fore-foot. Consequently, merely adjusting arch support and cushioning may inadequately address structural and motive issues associated with the fore-foot, e.g. support of the full body weight on the plantar portion of the foot, or propulsion accompanying the transfer of body weight from one foot to another through “pushing off.”

SUMMARY OF THE INVENTION

A shoe sole is coupled with an upper to define a foot compartment characterized by a fore-foot portion associable with metatarsals and phalanges, a mid-foot portion associable with the arch, and a hind-foot portion associable with the heel. A flexure plate, underlying the 2^(nd), 3^(rd), and 4^(th) metatarsal-phalangeal joints of a foot when enclosed within the foot compartment, is disposed within the fore-foot portion between the foot compartment and the outer surface of the sole. During bipedal locomotion, the flexure plate deforms in response to the transfer of a wearer's weight from the mid-foot portion through the fore-foot portion, and rebounds in response to the transfer of the wearer's weight off the fore-foot portion. The deforming and rebounding of the flexure plate enables controlled transfer of the wearer's weight from the mid-foot portion sequentially to the little toe, the big toe, and the three middle toes.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a side elevation view of a shoe comprising a sole and an upper defining a fore-foot portion, a mid-foot portion, and a hind-foot portion according to an exemplary embodiment of the invention.

FIG. 2 is a plan view of the sole of the shoe illustrated in FIG. 1.

FIG. 3 is a schematic plan view of a flexure plate and a bifurcated portion of a sole in relationship to the foot of a wearer of the shoe illustrated in FIG. 1.

FIG. 4 is a somewhat schematic front elevation exploded view of the flexure plate and bifurcated portion of a sole in relationship to the wearer's foot.

FIG. 5 is a plan view similar to FIG. 2 of a shoe sole incorporating a flexure plate according to an alternate exemplary embodiment of the invention.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

By way of introduction, and not as a limitation on the description herein of the embodiments of the invention or the scope of the claims, the human foot comprises the phalanges, or toe bones, and five metatarsals, each metatarsal associated with a single toe. The phalanges are connected to the metatarsals through metatarsal-phalangeal joints. Thus, the big toe is associated with a 1^(st) metatarsal-phalangeal joint, the 2^(nd) toe is associated with a 2^(nd) metatarsal-phalangeal joint, and so on. The “head” of the metatarsal is that part of the metatarsal adjacent the phalanges. When viewed from the front of the toes, the metatarsal-phalangeal joints may define a shallow downward-facing transverse metatarsal arch.

The invention may be described herein in the context of a generic shoe. Any reference herein to a “shoe” or to “footwear” may be construed to include men's, women's, and children's shoes and hoots, winter footwear, oxfords, cowboy boots, work shoes, flats, loafers, sandals, safety shoes, athletic shoes, tennis shoes, and the like, and the use of any such terminology may not be construed as limiting on the scope of the claims.

As used herein, the term “sole” will refer to the bottom part of a shoe for underlying, supporting, and protecting a foot. The sole may comprise a single unified structure extending from a foot compartment for enclosing a. foot to an outer surface for contact with the ground. Alternatively, the sole may be layered or may comprise one or more of a removable or integral insole, a midsole, an outsole, a removable insert, and the like. An upper may be attached to the sole to define, in part, the foot compartment.

An ideal weight support progression during walking contact of a foot with a supporting surface may begin with contact laterally along the heel. As the foot pitches forward, this lateral contact, and the associated weight support location, may proceed toward, and may eventually implicate, the 5^(th) toe, i.e. the little toe. The line of contact may translate medially from the lateral edge of the foot to the 1^(st) metatarsal head, i.e. the “ball” of the big toe. At the initiation of lift-off of the heel, the metatarsal-phalangeal joints may bear the entire weight of the body, with approximately 60% of the weight that is supported by the metatarsal heads directed to the 1^(st) metatarsal head. The transverse metatarsal arch may moderate the weight that is supported by 2^(nd), 3^(rd), and 4^(th) metatarsals. Continued forward pitching of the foot may collapse the transverse metatarsal arch, resulting in splaying of the 2^(nd), 3^(rd), and 4^(th) toes, At toe-off, weight may continue to be supported through the big toe during forward propulsion. The foot may then swing forward to repeat the weight support progression.

Turning now to the figures, and in particular to FIG. 1, a shoe 10 is illustrated that may comprise an upper 12 and a sole 14 according to an exemplary embodiment of the invention. For simplicity. FIG. 1 illustrates a unified sole, although the sole may comprise a layered structure comprising one or more of a removable or integral insole, a midsole, an outsole, a removable insert, and the like.

The upper 12 and sole 14 may be coupled together in a known manner to define a foot compartment 26 that may define a fore-foot portion 16, a mid-foot portion 18, and a hind-foot portion 20. The fore-foot portion 16 may be associated with the metatarsals and phalanges. The mid-foot portion may begin with the calcaneal-cuboid joint and end at the beginning of the metatarsals. The hind-foot portion may begin at the ankle joint and end at the calcaneal-cuboid joint, including the calcaneus, or heel bone. Further references herein to the fore-foot, mid-foot, and hind-foot portions may be construed as incorporating the aforementioned anatomical descriptions, unless otherwise noted herein.

The sole 14 may be fabricated of a material having suitable properties for the purposes described herein, such as abrasion resistance, compressibility, resiliency, flexibility, durability and the like. An example of a suitable material may include a polyurethane. Other traditional sole materials may be utilized, e.g. leather and rubber. The sole 14 may include an outer surface 22 for communication with a supporting surface upon which the shoe 10 and a wearer of the shoe may be supported.

Referring now to FIG. 2, the sole 14 may be characterized by a flexure plate 24, illustrated as a metatarsal arch plate, and a bifurcated sole 27. The flexure plate 24 may be a somewhat rectangular body incorporated into the sole 14 within the fore-foot portion 16. The bifurcated sole 27 may include a medial fore-foot bed 28 and a lateral fore-foot bed 30. The flexure plate 24 may traverse the fore-foot portion 16 to extend from the medial fore-foot bed 28 to the lateral fore-foot bed 30.

The medial fore-foot bed 28 may be configured to underlie the phalanges of the big toe and at least a portion of the 1^(st) metatarsal of a foot enclosed within the foot compartment 26, The lateral fore-foot bed 30 may be configured to underlie the 2^(nd), 3^(rd), 4^(th), and 5^(th) phalanges, and at least a portion of the 2^(nd), 3^(rd), 4^(th), and 5^(th) metatarsals, of a foot enclosed within the foot compartment 26. The medial fore-foot bed 28 and the lateral fore-foot bed 30 may be configured to optimize therapeutic benefits from the fore-foot beds 28, 30, to customize the shoe 10 for varying foot sizes and shapes, to accommodate and correct foot and leg conditions requiring therapy, and the like. The configurations of the medial fore-foot bed 28 and the lateral fore-foot bed 30 illustrated herein are exemplary only, may vary from the illustrations, and are not to be construed as exclusive or in any way limiting on the claims.

The medial fore-foot bed 28 and the lateral fore-foot bed 30 may comprise differing materials characterized by differing properties. The hardness of the medial fore-foot bed 28 may be greater than the hardness of the lateral fore-foot bed 30. For example, the medial fore-foot bed 28 may have a Shore durometer hardness of 50, and the lateral fore-foot bed 30 may have a Shore durometer hardness of 40. The hardness of the medial fore-foot bed 28 may differ from the hardness of the lateral fore-foot bed 30 by between 5 and 20 as determined by a Shore durometer.

The medial fore-foot bed 28 and the lateral fore-foot bed 30 may be contiguous along a sole discontinuity 48. Thus, the sole discontinuity 48 may correlate with the transition from a material having a 1^(st) Shore durometer hardness to a material having a 2^(nd) Shore durometer hardness. The sole discontinuity 48 may extend from the forward end of the fore-foot portion 16 into the mid-foot portion 18.

The sole discontinuity 48 may be a straight line or curved line as illustrated in FIG. 2. Alternatively, the discontinuity 48 may constitute a separation between the medial fore-foot bed 28 and the lateral fore-foot bed 30. which may be characterized by a constant width, or a variable width as illustrated in FIG. 3. The sole discontinuity 48 may extend from within the sole 14 to the outer surface 22, or may be fully incorporated in the sole 14 or in a portion of the sole 14.

Referring to FIGS. 3 and 4, the metatarsal-phalangeal joints 46 may be characterized by a shallow downward-facing transverse metatarsal arch 52 along the plantar area of the foot, associated with and supportable by the flexure plate 24. The flexure plate 24 may be a 1-piece thin non-planar body terminating in a medial plate end 32 and a lateral plate end 34. The flexure plate 24 may be characterized by a 2-dimensional curvature, i.e. an arch, extending longitudinally from the medial plate end 32 to the lateral plate end 34. Alternatively, the flexure plate 24 may be characterized by a 3-dimensional curvature, i.e. a concavity or dome, as hereinafter described. The flexure plate 24 may have an overall square configuration or an overall rectangular configuration for accommodating differences in foot characteristics such as foot length, foot width, toe length, transverse metatarsal arch geometry, and the like. The flexure plate 24 may be curved or concave in the direction of the outer surface 22 of the sole 14,

The flexure plate 24 may be fabricated of a suitable material, e.g., ethylene-vinyl acetate, exhibiting elastomeric properties such as softness and flexibility, low temperature toughness, and stress-crack resistance suitable for the purposes described herein. Other flexure plate materials may include spring steel characterized by a high modulus of elasticity, or other materials exhibiting relevant properties, such as strength and flexibility, suitable for the purposes described herein. The flexure plate 24 may be incorporated into the sole 14 between the outer surface 22 of the sole 14 and the foot compartment 26.

The sole 14 may incorporate the flexure plate 24 by employing a suitable fabrication process, such as injection molding. Depending upon the structure of the sole 14, the flexure plate 24 may be incorporated into a removable insole, an integrated insole and outsole, a removable insert, and the like. For example, the flexure plate 24 may be incorporated into a unified, single-layer sole 14 at a depth that may be selected based upon, for example, the relative flexibility of the sole material and the flexure plate material, the measure of support to be provided to the foot, the area of the foot over which the support is to he provided, and like considerations. Alternatively, the flexure plate 24 may he incorporated into a readily removable insole enabling efficient and economical modification or replacement of the flexure plate 24 in response to changes in physiology, posture, gait, and the like.

As illustrated in FIG. 3, the flexure plate 24 may be characterized as a 4-sided figure, one or more edges of which may, in plan view, be curved, with curved corners. The flexure plate 24 may be characterized by a 2-dimensional curvature or a 3-dimensional curvature, as hereinbefore described. Alternatively, the flexure plate 24 may include a selected number and dimensions of edges and corners to enable control of the location of one or more flexure points, control of flexure magnitude under differing loading conditions, control of the width and length of the flexure plate 24 in view of the support to be provided to one or more of the toes, and the like, based upon one or more of the factors hereinbefore described.

FIG. 3 also illustrates an exemplary foot 50 characterized by a big toe 36, a 2^(nd) toe 38, a 3^(rd) toe 40, a 4^(th) toe 42, and a 5^(th) toe 44. As previously described, the toes 36, 38, 40, 42, 44 are characterized by the phalanges (not shown). The phalanges are connected to the metatarsals (not shown) at the metatarsal-phalangeal joints. During walking, as contact with a supporting surface progresses from the heel to the ends of the toes, the weight of a person may be supported by the metatarsal heads. The flexure plate 24 may be incorporated into the sole 14 so that the metatarsal heads are supported by the flexure plate 24. The curvature of the flexure plate 24 may mimic the curvature of the transverse metatarsal arch, thereby optimizing stability, control, support, and comfort provided to the transverse metatarsal arch 52 by the flexure plate 24. The flexure plate 24 may be configured to support only the 2^(nd), 3^(rd), and 4^(th) toes, and may be offset somewhat from the metatarsal-phalangeal joints 46 based upon one or more of the factors hereinbefore described.

The hardness of the medial fore-foot bed 28 may facilitate “push off” by the big toe, increase fore-foot leverage, and stabilize the interaction of the toes.

Bifurcation of the sole 27 may intersect, the outer surface 22, thereby selectively enabling the fore-foot beds 28, 30 to comprise either the same material, or differing materials. It should be noted that bifurcation of the sole 27 may be effected for a sole comprising the same material for both the medial fore-foot bed 28 and lateral fore-foot bed 30. Alternatively, bifurcation of the sole 27 may characterize an internal portion of the sole 14, the insole, the midsole, and the like. The medial fore-foot bed 28 and lateral fore-foot bed 30 may be incorporated into the sole 14 to constitute respective portions of the outer surface 22. The medial and lateral fore-foot beds 28, 30 may be separated by the sole discontinuity 48, or may be joined to minimize separation, or optimize strength and durability. As illustrated in the figures, the flexure plate 24 may extend from an area associated with the medial fore-foot bed 28 to an area associated with the lateral fore-foot bed 30. The sole discontinuity 48 may extend beyond the mid-foot portion 18 into the hind-foot portion 20.

Referring now to FIG. 5, the sole 14 may alternatively be configured with a flexure plate in the form of a toe control concavity 54 in a location generally correlating with the hereinbefore: described location of the flexure: plate 24. The flexure plate 54 may replace the flexure: plate 24 in one or both shoes. The sole 14 comprising the flexure plate 54 may incorporate one or more of the aforementioned features, such as an outer surface 22, a bifurcated sole 27 having medial and lateral fore-foot beds 28, 30, and the like.

The flexure plate 54 is illustrated in FIG. 5 as comprising a somewhat triangular area in the fore-foot portion 16 although the flexure plate 54 may be characterized by suitable configurations other than triangular. The flexure plate 54 may extend into the sole 14, and may define an arch traversing the medial and lateral fore-foot beds 28, 30. Deforming of the flexure plate 54 and sole 14 may replicate the deforming of the flexure plate 24. However, the deformation response of the flexure plate 54 to a selected load may differ somewhat from the deformation response of the flexure plate 24 to the same load. For example, the flexure plate 24 may bend along a longitudinal axis intersecting the medial plate end 32 and the lateral plate end 34. In contrast, the flexure plate 54 may flatten along a large number, even an infinite number, of axes, with bending occurring along differing axes as the weight of a wearer of the shoe translates along the sole 14.

As previously described herein, walling contact of a toot with a supporting surface may begin with contact laterally along the heel. As the foot pitches forward, this lateral contact, may proceed toward, and may eventually implicate, the 5^(th) toe, i.e. the little toe. The line of contact may translate medially from the lateral edge of the foot to the 1^(st) metatarsal head, i.e. the “ball” of the big toe. At the initiation of lift-off of the heel, the metatarsal-phalangeal joints may bear the entire weight of the body, with approximately 60% of the weight that is supported by the metatarsal heads directed to the 1^(st) metatarsal head. The transverse metatarsal arch may moderate the weight that is supported by the 2^(nd), 3^(rd), and 4^(th) metatarsals. Continued forward pitching of the foot may collapse the transverse metatarsal arch, resulting in splaying of the 2^(nd), 3^(rd), and 4^(th) toes. At toe-off, the big toe may continue to support the weight of the body during forward propulsion. As weight is transferred to the other foot, the first foot may swing forward to repeat the weight support progression,

Deforming and rebounding of the flexure plates 24, 54 may control movement and weight transfer from the heel to the toes to thereby optimize bipedal locomotion, correct improper posture and gait, eliminate pain, and improve functionality. Deforming of the flexure plates 24, 54 may be a function of at least one of the weight of a wearer of the shoe, the width of the fore-foot portion of the shoe, the elasticity of the flexure plate, the rebound length and width of the flexure plate, the curvature of the flexure plate, the flexibility of the sole including the fore-foot beds 28, 30, and like factors. A bifurcated sole incorporating fore-foot portions having differing harnesses may also contribute to the above-described movement and weight transfer control, and may enable refinement of the functionality of an item of footwear to facilitate optimization of bipedal locomotion, posture and gait correction, and pain reduction. An item of footwear may incorporate both a flexure plate and a bifurcated sole, or may incorporate only one of these features.

While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation. Reasonable variation and modification are possible within the scope of the forgoing disclosure and drawings without departing from the spirit of the invention, which is defined in the appended claims. 

What is claimed is:
 1. A shoe (10) comprising: a sole (14), including an outer surface (22) communicable with a supporting surface upon which the shoe (10) and a wearer of the shoe (10) are supportable; an upper (12) coupled with the sole (14) to cooperatively define afoot compartment (26) characterized by a fore-foot portion (16), a mid-foot portion (18), and a hind-foot portion (20), the fore-foot portion (16) associable with the metatarsals and phalanges of a foot (50); and a flexure plate (24, 54) disposed within the fore-foot portion (16) between the foot compartment (26) and the outer surface (22) of the sole (14) to underlie the 2^(nd), 3^(rd), and 4^(th) metatarsal-phalangeal joints of a foot (50) when enclosed within the foot compartment (26); whereby during bipedal locomotion, the flexure plate (24, 54) is deformable in response to the transfer of a weight of a wearer of the shoe (10) from the mid-foot portion (18) through the fore-foot portion (16), and is reboundable in response to the transfer of a weight of a wearer of the shoe (10) off the fore-foot portion (16); and whereby during bipedal locomotion, a weight of a wearer of the shoe (10) is transferable from the mid-foot portion (18) sequentially to the little toe (44), the big toe (36), and the three middle toes (38, 40, 42) by the deforming and rebounding of the flexure plate (24, 54).
 2. A shoe (10) in accordance with claim 1 wherein the deforming and rebounding of the flexure plate (24, 54) varies as a weight of a wearer of the shoe (10) is transferred from the mid-foot portion (18) through and off the fore-foot portion (16).
 3. A shoe (10) in accordance with claim 2 wherein the deforming and rebounding of the flexure plate (24, 54) is a function of at least one of a weight of a wearer of the shoe (10), the width of the fore-foot portion (16) of the shoe (10), the modulus of elasticity of the flexure plate (24, 54), the rebound length and width of the flexure plate (24, 54), the curvature of the flexure plate (24, 54), and the flexibility of the sole (14).
 4. A shoe (10) in accordance with claim 1, and further comprising an inner sole wherein the flexure plate (24, 54) is disposed between the inner sole and the outer surface (22) of the sole (14).
 5. A shoe (10) in accordance with claim 4 wherein the flexure plate 24 54 is curved in the direction of the outer surface (22) of the sole (14).
 6. A shoe (10) in accordance with claim I wherein the flexure plate
 24. 54 is curved in the direction of the outer surface (22) of the sole (14).
 7. A shoe (10) in accordance with claim 1 wherein a portion of the sole (14) underlies the fore-foot portion (16), and comprises a medial fore-foot bed (28) and a lateral fore-foot bed (30).
 8. A shoe (10) in accordance with claim 7 wherein the medial fare-foot bed (28) underlies the phalanges of the big toe (36) and at least a portion of the 1^(st) metatarsal of a foot (50) when enclosed within the foot compartment (26).
 9. A shoe (10) in accordance with claim 8 wherein the lateral fore-foot bed (30) underlies the 2^(nd), 3^(rd), 4^(th), and 5^(th) phalanges and at least a portion of the 2^(nd), 3^(rd), 4^(th), and 5^(th) metatarsals of a foot (50) when enclosed within the foot compartment (26).
 10. A shoe (10) in accordance with claim 7 wherein a hardness of the medial fore-foot bed (28) is greater than a. hardness of the lateral fore-foot bed (30).
 11. A shoe (10) in accordance with claim 10 wherein the hardness of the medial fore-foot bed. (28) differs from the hardness of the lateral fore-foot bed (30) by between 5 and 20 durorneter.
 12. A shoe (10) comprising. a sole (14), including an outer surface (22) communicable with a supporting surface upon which the shoe (10) and a. wearer of the shoe (10) are supportable; and an upper (12) coupled with the sole (14) to cooperatively define a foot compartment (26) characterized by a fore-foot portion (16), a mid-foot portion (18), and a hind-foot portion (20), the fore-foot portion (16) associable with metatarsals and phalanges of a foot (50); wherein the sole (14) is characterized by a flexure plate (54) disposed within the fore-foot portion (16) between the foot compartment (26) and the outer surface (22) of the sole (14) to underlie the 2^(nd), 3^(rd), and 4^(th) metatarsal-phalangeal joints of a foot (50) when enclosed within the foot compartment (26); and whereby, during bipedal locomotion, the flexure plate (54) facilitates flexing of the sole (14) and splaying of the 2^(nd), 3^(rd), and 4^(th) metatarsals and phalanges of a foot (50) when enclosed within the foot compartment (26).
 13. A shoe (10) in accordance with claim 12 wherein the flexure plate (54) is intersected by the outer surface (22) of the sole (14).
 14. A shoe (10) in accordance with claim 12 wherein the flexure of the sole (14) facilitated by the deforming of the plate (54) varies as the weight of a wearer of the shoe (10) is transferred from the mid-foot portion (18) through and off the fore-foot portion (16).
 15. A shoe (10) in accordance with claim 14 wherein the flexure of the sole (14) is a function of at least one of a weight of a wearer of the shoe (10), a width of the flexure plate (54), a depth of the flexure plate (54) in the sole (14), and the flexibility of the sole (14).
 16. A shoe (10) in accordance with claim 12, and further comprising an inner sole wherein the flexure plate (54) is disposed between the inner sole and the outer surface (22) of the sole (14).
 17. A shoe (10) in accordance with claim 16 wherein the flexure plate (54) is concave in the direction of the outer surface (22) of the sole (14).
 18. A shoe (10) in accordance with claim 12 wherein the flexure plate (54) is concave in the direction of the outer surface (22) of the sole (14).
 19. A shoe (10) in accordance with claim 12 wherein a portion of the sole (14) underlies the fore-foot portion (16), and comprises a medial fore-foot bed (28) and a lateral fore-foot. bed (30).
 20. A shoe (10) in accordance with claim 19 wherein the medial fore-foot bed (28) underlies the phalanges of the big toe (36) and at least a portion of the l metatarsal of a foot (50) when enclosed within the foot compartment (26).
 21. A shoe (10) in accordance with claim 20 wherein the lateral fore-foot bed (30) underlies the 2^(nd), 3^(rd), 4^(th), and 5^(th) phalanges and at least a portion of the 2^(nd), 3^(rd), 4^(th), and 5^(th) metatarsals of a foot (50) when enclosed within the foot compartment (26).
 22. A shoe (10) in accordance with claim 19 wherein a hardness of the medial fore-foot bed (28) is greater than a hardness of the lateral fore-foot bed (30).
 23. A shoe (10) in accordance with claim 22 wherein the hardness of the medial fore-foot bed (28) differs from the hardness of the lateral fore-foot bed (30) by between 5 and 20 durometer. 